diff --git a/.upgrade.yml b/.upgrade.yml
new file mode 100644
index 0000000..152aedf
--- /dev/null
+++ b/.upgrade.yml
@@ -0,0 +1,25 @@
+mappings:
+  DMS: Sunnysideup\DMS\DMS
+  DMSShortcodeHandler: Sunnysideup\DMS\DMSShortcodeHandler
+  MigrateToDocumentSetsTask: Sunnysideup\DMS\Tasks\MigrateToDocumentSetsTask
+  DMSJsonField: Sunnysideup\DMS\Forms\DMSJsonField
+  DMSGridFieldAddNewButton: Sunnysideup\DMS\Cms\DMSGridFieldAddNewButton
+  DMSUploadField_ItemHandler: Sunnysideup\DMS\Cms\DMSUploadField_ItemHandler
+  DMSGridFieldEditButton: Sunnysideup\DMS\Cms\DMSGridFieldEditButton
+  DMSDocumentAddExistingField: Sunnysideup\DMS\Cms\DMSDocumentAddExistingField
+  DocumentHTMLEditorFieldToolbar: Sunnysideup\DMS\Cms\DocumentHTMLEditorFieldToolbar
+  DMSDocumentAddController: Sunnysideup\DMS\Cms\DMSDocumentAddController
+  DMSUploadField: Sunnysideup\DMS\Cms\DMSUploadField
+  DMSDocumentAdmin: Sunnysideup\DMS\Cms\DMSDocumentAdmin
+  DMSGridFieldDetailForm_ItemRequest: Sunnysideup\DMS\Cms\DMSGridFieldDetailForm_ItemRequest
+  DMSInterface: Sunnysideup\DMS\Interface\DMSInterface
+  DMSDocumentInterface: Sunnysideup\DMS\Interface\DMSDocumentInterface
+  DMSDocumentTaxonomyExtension: Sunnysideup\DMS\Extensions\DMSDocumentTaxonomyExtension
+  DMSTaxonomyTypeExtension: Sunnysideup\DMS\Extensions\DMSTaxonomyTypeExtension
+  DMSSiteTreeExtension: Sunnysideup\DMS\Extensions\DMSSiteTreeExtension
+  FileNotFoundException: Sunnysideup\DMS\Exceptions\FileNotFoundException
+  DMSDocument_versions: Sunnysideup\DMS\Model\DMSDocument_versions
+  DMSDocument: Sunnysideup\DMS\Model\DMSDocument
+  DMSDocument_Controller: Sunnysideup\DMS\Model\DMSDocument_Controller
+  DMSDocumentSet: Sunnysideup\DMS\Model\DMSDocumentSet
+  ShortCodeRelationFinder: Sunnysideup\DMS\Tools\ShortCodeRelationFinder
diff --git a/src/Cms/DMSDocumentAddController.php b/src/Cms/DMSDocumentAddController.php
index 61d4b2a..149cea7 100644
--- a/src/Cms/DMSDocumentAddController.php
+++ b/src/Cms/DMSDocumentAddController.php
@@ -1,5 +1,27 @@
 <?php
 
+namespace Sunnysideup\DMS\Cms;
+
+use LeftAndMain;
+use SiteTree;
+use DMSDocumentSet;
+use Requirements;
+use Form;
+use FieldList;
+use TabSet;
+use Tab;
+use LiteralField;
+use HiddenField;
+use Controller;
+use ArrayData;
+use CMSPageEditController;
+use Convert;
+use DMSDocument;
+use Config;
+use Member;
+use Permission;
+
+
 /**
  * @package dms
  */
diff --git a/src/Cms/DMSDocumentAddExistingField.php b/src/Cms/DMSDocumentAddExistingField.php
index c279457..3a2e299 100644
--- a/src/Cms/DMSDocumentAddExistingField.php
+++ b/src/Cms/DMSDocumentAddExistingField.php
@@ -1,5 +1,12 @@
 <?php
 
+namespace Sunnysideup\DMS\Cms;
+
+use CompositeField;
+use TreeDropdownField;
+use Requirements;
+
+
 class DMSDocumentAddExistingField extends CompositeField
 {
     public $useFieldContext = true;
diff --git a/src/Cms/DMSDocumentAdmin.php b/src/Cms/DMSDocumentAdmin.php
index 10fe0a8..98a17b7 100644
--- a/src/Cms/DMSDocumentAdmin.php
+++ b/src/Cms/DMSDocumentAdmin.php
@@ -1,5 +1,14 @@
 <?php
 
+namespace Sunnysideup\DMS\Cms;
+
+use ModelAdmin;
+use Requirements;
+use CMSForm;
+use GridField;
+use SiteTree;
+
+
 class DMSDocumentAdmin extends ModelAdmin
 {
     private static $managed_models = array(
diff --git a/src/Cms/DMSGridFieldAddNewButton.php b/src/Cms/DMSGridFieldAddNewButton.php
index aafa9da..acc84d5 100644
--- a/src/Cms/DMSGridFieldAddNewButton.php
+++ b/src/Cms/DMSGridFieldAddNewButton.php
@@ -1,5 +1,15 @@
 <?php
 
+namespace Sunnysideup\DMS\Cms;
+
+use GridFieldAddNewButton;
+use GridField_HTMLProvider;
+use Controller;
+use DMSDocumentSet;
+use CMSPageEditController;
+use ArrayData;
+
+
 class DMSGridFieldAddNewButton extends GridFieldAddNewButton implements GridField_HTMLProvider
 {
     /**
diff --git a/src/Cms/DMSGridFieldDetailForm.php b/src/Cms/DMSGridFieldDetailForm.php
index 94c8ede..ea11ce3 100644
--- a/src/Cms/DMSGridFieldDetailForm.php
+++ b/src/Cms/DMSGridFieldDetailForm.php
@@ -1,5 +1,11 @@
 <?php
 
+namespace Sunnysideup\DMS\Cms;
+
+use GridFieldDetailForm_ItemRequest;
+use ShortCodeRelationFinder;
+
+
 /**
  * Custom ItemRequest class the provides custom delete behaviour for the CMSFields of DMSDocument
  */
diff --git a/src/Cms/DMSGridFieldEditButton.php b/src/Cms/DMSGridFieldEditButton.php
index 1519907..44fd47f 100755
--- a/src/Cms/DMSGridFieldEditButton.php
+++ b/src/Cms/DMSGridFieldEditButton.php
@@ -1,5 +1,13 @@
 <?php
 
+namespace Sunnysideup\DMS\Cms;
+
+use GridFieldEditButton;
+use GridField_ColumnProvider;
+use ArrayData;
+use Controller;
+
+
 class DMSGridFieldEditButton extends GridFieldEditButton implements GridField_ColumnProvider
 {
 
diff --git a/src/Cms/DMSUploadField.php b/src/Cms/DMSUploadField.php
index c736091..85224d6 100644
--- a/src/Cms/DMSUploadField.php
+++ b/src/Cms/DMSUploadField.php
@@ -1,5 +1,23 @@
 <?php
 
+namespace Sunnysideup\DMS\Cms;
+
+use UploadField;
+use DMS;
+use DMSDocument;
+use DMSDocumentSet;
+use SS_HTTPRequest;
+use SS_Object;
+use Exception;
+use SS_HTTPResponse;
+use Convert;
+use ArrayList;
+use Requirements;
+use FieldList;
+use FormAction;
+use Validator;
+
+
 /**
  * Field for uploading files into a DMSDocument. Replacing the existing file.
  * Not ideally suited for the purpose, as the base implementation
diff --git a/src/Cms/DMSUploadField_ItemHandler.php b/src/Cms/DMSUploadField_ItemHandler.php
index 374a4ab..0ab87d5 100644
--- a/src/Cms/DMSUploadField_ItemHandler.php
+++ b/src/Cms/DMSUploadField_ItemHandler.php
@@ -1,5 +1,12 @@
 <?php
 
+namespace Sunnysideup\DMS\Cms;
+
+use UploadField_ItemHandler;
+use DMSDocument;
+use Form;
+
+
 class DMSUploadField_ItemHandler extends UploadField_ItemHandler
 {
     private static $allowed_actions = array(
diff --git a/src/Cms/DocumentHtmlEditorFieldToolbar.php b/src/Cms/DocumentHtmlEditorFieldToolbar.php
index e4bb19d..b825e8b 100644
--- a/src/Cms/DocumentHtmlEditorFieldToolbar.php
+++ b/src/Cms/DocumentHtmlEditorFieldToolbar.php
@@ -1,4 +1,12 @@
 <?php
+
+namespace Sunnysideup\DMS\Cms;
+
+use Extension;
+use Form;
+use HiddenField;
+use DMS;
+
 /**
  * Extends the original toolbar with document picking capability - modified lines are commented.
  */
diff --git a/src/DMS.php b/src/DMS.php
index 0a251ce..6e7e22b 100644
--- a/src/DMS.php
+++ b/src/DMS.php
@@ -1,4 +1,15 @@
 <?php
+
+namespace Sunnysideup\DMS;
+
+use SS_Object;
+use DMSInterface;
+use Director;
+use FileNotFoundException;
+use DMSDocument;
+use SiteTree;
+use Config;
+
 class DMS extends SS_Object implements DMSInterface
 {
     /**
diff --git a/src/DMSShortcodeHandler.php b/src/DMSShortcodeHandler.php
index 7c1564b..0732364 100644
--- a/src/DMSShortcodeHandler.php
+++ b/src/DMSShortcodeHandler.php
@@ -1,5 +1,12 @@
 <?php
 
+namespace Sunnysideup\DMS;
+
+use ShortcodeParser;
+use DMSDocument;
+use ErrorPage;
+
+
 /**
  * Handles replacing `dms_document_link` shortcodes with links to the actual
  * document.
diff --git a/src/Exceptions/FileNotFoundException.php b/src/Exceptions/FileNotFoundException.php
index b50bf65..4ede8fd 100644
--- a/src/Exceptions/FileNotFoundException.php
+++ b/src/Exceptions/FileNotFoundException.php
@@ -1,4 +1,9 @@
 <?php
+
+namespace Sunnysideup\DMS\Exceptions;
+
+use Exception;
+
 /**
  * Simple exception extension so that we can tell the difference between internally
  * raised exceptions and those thrown by DMS.
diff --git a/src/Extensions/DMSDocumentTaxonomyExtension.php b/src/Extensions/DMSDocumentTaxonomyExtension.php
index 4fddbbf..c4e0400 100644
--- a/src/Extensions/DMSDocumentTaxonomyExtension.php
+++ b/src/Extensions/DMSDocumentTaxonomyExtension.php
@@ -1,5 +1,14 @@
 <?php
 
+namespace Sunnysideup\DMS\Extensions;
+
+use DataExtension;
+use FieldList;
+use ListboxField;
+use TaxonomyTerm;
+use Config;
+
+
 
 /**
   * ### @@@@ START REPLACEMENT @@@@ ###
diff --git a/src/Extensions/DMSSiteTreeExtension.php b/src/Extensions/DMSSiteTreeExtension.php
index 75f03d7..27cbda5 100644
--- a/src/Extensions/DMSSiteTreeExtension.php
+++ b/src/Extensions/DMSSiteTreeExtension.php
@@ -1,5 +1,19 @@
 <?php
 
+namespace Sunnysideup\DMS\Extensions;
+
+use DataExtension;
+use FieldList;
+use Permission;
+use Member;
+use GridField;
+use GridFieldConfig_RelationEditor;
+use DMSDocumentSet;
+use Deprecation;
+use ArrayList;
+use Versioned;
+
+
 /**
  * @package dms
  */
diff --git a/src/Extensions/DMSTaxonomyTypeExtension.php b/src/Extensions/DMSTaxonomyTypeExtension.php
index 7a7936a..10f8348 100644
--- a/src/Extensions/DMSTaxonomyTypeExtension.php
+++ b/src/Extensions/DMSTaxonomyTypeExtension.php
@@ -1,4 +1,11 @@
 <?php
+
+namespace Sunnysideup\DMS\Extensions;
+
+use DataExtension;
+use Config;
+use TaxonomyType;
+
 /**
  * Creates default taxonomy type records if they don't exist already
  */
diff --git a/src/Forms/DMSJsonField.php b/src/Forms/DMSJsonField.php
index 31de0a9..aa6f515 100644
--- a/src/Forms/DMSJsonField.php
+++ b/src/Forms/DMSJsonField.php
@@ -1,5 +1,12 @@
 <?php
 
+namespace Sunnysideup\DMS\Forms;
+
+use CompositeField;
+use FieldList;
+use Convert;
+
+
 /**
  * Combines form inputs into a key-value pair
  */
diff --git a/src/Interface/DMSDocumentInterface.php b/src/Interface/DMSDocumentInterface.php
index 58be684..3984263 100644
--- a/src/Interface/DMSDocumentInterface.php
+++ b/src/Interface/DMSDocumentInterface.php
@@ -1,4 +1,9 @@
 <?php
+
+namespace Sunnysideup\DMS\Interface;
+
+
+
 /**
  * Interface for a DMSDocument used in the Document Management System. A DMSDocument is create by storing a File
  * object in an instance of the DMSInterface. All write operations on the DMSDocument create a new relation, so we
diff --git a/src/Interface/DMSInterface.php b/src/Interface/DMSInterface.php
index 09be427..fbc3fa1 100644
--- a/src/Interface/DMSInterface.php
+++ b/src/Interface/DMSInterface.php
@@ -1,4 +1,9 @@
 <?php
+
+namespace Sunnysideup\DMS\Interface;
+
+use SiteTree;
+
 /**
  * When storing a document, the DMS sucks up the file and stores it separately from the assets section.
  * When initializing the DMS, it should create some kind of storage system. For file-based storage, that could be
diff --git a/src/Model/DMSDocument.php b/src/Model/DMSDocument.php
index da13855..4bcd251 100644
--- a/src/Model/DMSDocument.php
+++ b/src/Model/DMSDocument.php
@@ -1,5 +1,51 @@
 <?php
 
+namespace Sunnysideup\DMS\Model;
+
+use DataObject;
+use DMSDocumentInterface;
+use Member;
+use Permission;
+use DB;
+use URLSegmentFilter;
+use Controller;
+use Director;
+use Versioned;
+use SS_Datetime;
+use DBField;
+use Exception;
+use DMS;
+use Requirements;
+use FieldList;
+use ShortCodeRelationFinder;
+use TextField;
+use TextareaField;
+use UploadField;
+use Config;
+use OptionsetField;
+use DMSUploadField;
+use GridFieldConfig;
+use GridFieldToolbarHeader;
+use GridFieldSortableHeader;
+use GridFieldDataColumns;
+use GridFieldPaginator;
+use GridFieldDetailForm;
+use GridField;
+use DatetimeField;
+use FieldGroup;
+use LiteralField;
+use DropdownField;
+use CompositeField;
+use File;
+use ReadonlyField;
+use DateField_Disabled;
+use ArrayList;
+use GridFieldConfig_RelationEditor;
+use DMSGridFieldEditButton;
+use GridFieldAddExistingAutocompleter;
+use Convert;
+
+
 /**
  * @package dms
  *
diff --git a/src/Model/DMSDocumentSet.php b/src/Model/DMSDocumentSet.php
index 443fb9d..9c26355 100644
--- a/src/Model/DMSDocumentSet.php
+++ b/src/Model/DMSDocumentSet.php
@@ -1,4 +1,40 @@
 <?php
+
+namespace Sunnysideup\DMS\Model;
+
+use DataObject;
+use FieldList;
+use LiteralField;
+use GridFieldConfig;
+use GridFieldButtonRow;
+use GridFieldToolbarHeader;
+use GridFieldFilterHeader;
+use GridFieldSortableHeader;
+use GridFieldDataColumns;
+use DMSGridFieldEditButton;
+use GridFieldDeleteAction;
+use GridFieldDetailForm;
+use GridFieldPaginatorWithShowAll;
+use GridFieldPaginator;
+use GridFieldSortableRows;
+use GridFieldOrderableRows;
+use CMSPageEditController;
+use Controller;
+use GridField;
+use DMSGridFieldAddNewButton;
+use HiddenField;
+use DMS;
+use Requirements;
+use Member;
+use ListboxField;
+use DMSJsonField;
+use FieldGroup;
+use DropdownField;
+use Convert;
+use DataList;
+use SS_Datetime;
+use Permission;
+
 /**
  * A document set is attached to Pages, and contains many DMSDocuments
  *
diff --git a/src/Model/DMSDocument_Controller.php b/src/Model/DMSDocument_Controller.php
index 603bda0..c3a9da0 100644
--- a/src/Model/DMSDocument_Controller.php
+++ b/src/Model/DMSDocument_Controller.php
@@ -1,5 +1,15 @@
 <?php
 
+namespace Sunnysideup\DMS\Model;
+
+use Controller;
+use Versioned;
+use Convert;
+use DataObject;
+use InvalidArgumentException;
+use SS_HTTPRequest;
+
+
 class DMSDocument_Controller extends Controller
 {
     /**
diff --git a/src/Model/DMSDocument_versions.php b/src/Model/DMSDocument_versions.php
index ed5fec1..2d2ca2a 100644
--- a/src/Model/DMSDocument_versions.php
+++ b/src/Model/DMSDocument_versions.php
@@ -1,5 +1,15 @@
 <?php
 
+namespace Sunnysideup\DMS\Model;
+
+use DataObject;
+use Controller;
+use Director;
+use DMS;
+use File;
+use DB;
+
+
 /**
  * DataObject to store versions of uploaded Documents.
  *
diff --git a/src/Tasks/MigrateToDocumentSetsTask.php b/src/Tasks/MigrateToDocumentSetsTask.php
index a19b497..a6b8d3f 100644
--- a/src/Tasks/MigrateToDocumentSetsTask.php
+++ b/src/Tasks/MigrateToDocumentSetsTask.php
@@ -1,4 +1,14 @@
 <?php
+
+namespace Sunnysideup\DMS\Tasks;
+
+use BuildTask;
+use SiteTree;
+use SQLSelect;
+use DMSDocument;
+use DMSDocumentSet;
+use Director;
+
 /**
  * This build task helps to migrate DMS data structures from DMS 1.x to 2.x which introduces document sets.
  *
diff --git a/src/Tools/ShortCodeRelationFinder.php b/src/Tools/ShortCodeRelationFinder.php
index fa978b9..51a277d 100644
--- a/src/Tools/ShortCodeRelationFinder.php
+++ b/src/Tools/ShortCodeRelationFinder.php
@@ -1,4 +1,12 @@
 <?php
+
+namespace Sunnysideup\DMS\Tools;
+
+use DataList;
+use DMS;
+use ClassInfo;
+use DataObject;
+
 /**
  * Finds {@link DataObject} instances using certain shortcodes
  * by fulltext-querying only fields which are capable of parsing shortcodes.